Chrysler: Rough Ride Over

While the Road Ahead Remains bumpy for Chrysler Group LLC, customers can expect a smoother ride from the '10 Dodge Ram heavy-duty pickup than from the outgoing model.

The Ram 2500 and 3500, available for the first time in crew-cab configuration, features the auto maker's inaugural application of fluid-filled body mounts. Positioned under the C-pillar, the glycol-filled mounts are supplied by Cooper Standard Automotive and could migrate to other models as Chrysler realigns its post-bankruptcy product strategy, insiders say.

Why did Chrysler engineers try to refine the auto maker's iconic workhorse? Because market research revealed consumers have high expectations for comfort, regardless of the vehicle segment.

When the auto maker launched a Six-Sigma project to guide the development of its new truck, “ride quality came right up to the top,” says Eric Keipper, manager-truck and powertrain noise, vibration and harshness.

And because damping represented a more cost-effective remedy than frame changes, body mounts were “a decent solution,” adds Kevin Mets, senior vehicle development manager-pickups and chassis cabs.

Chrysler zeroed in on the C-pillar because the area where it intersects with the frame is subject to bending, the bane of ride quality. But engineers discovered solid rubber body mounts fell short of their damping bogey.

So Chrysler enlisted Cooper's development expertise. “We gave them a target and they were able to match it,” Mets says.

But along the way, there were several bumps in the road, says Bernie Rice, Cooper's product-engineering director-NVH controls.

“What is unique about the application of a hydraulic mount for the body vs. a typical usage like on an engine, is that the weight on the mount varies significantly as the vehicle cab is loaded or unloaded,” Rice tells Ward's.

So the mount's design had to accommodate weight fluctuation without restricting the required fluid flow.

“The part had to fit within the existing environment in order to avoid frame changes,” he says, adding the component also must withstand extraordinarily high internal pressures, compounding the importance of sealing and material selection.

The result is a “best-of-both-worlds” design that features a load-carrying mount, mated to a hydraulic mount, Rice says.

Cooper and Chrysler claim the component generates up to four times the amount of damping expected of a typical hydraulic mount and reduces driver's seat vibration by as much as 60%.

As a bonus, the mount helps mitigate wheel hop, Mets says, while Rice points to potential fuel-economy improvement.

“We can reduce strain levels of both the frame and the body, thus permitting the use of lighter material for both,” Rice says.

Heavy-duty pickup sales are in decline, as with the rest of the industry. Chrysler delivered just over 16,000 units through May, down significantly from like-2008, says spokeswoman Carrie McElwee.

Chrysler's heavy-duty Ram lineup is carrying the load for the auto maker as one of its few new products this calendar year. But its introduction could pay dividends for vehicles still in development, or not yet conceived.

As Chrysler emerges from bankruptcy and re-establishes its footing under the umbrella of Fiat Auto Group, the heavy-duty Ram program has equipped engineers with “a real nice template” to address NVH issues, Mets says.

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